xy ≠ 0 , x > y

#### Quantity A

$\frac{1}{x}$

#### Quantity B

$\frac{1}{y}$

a ≠ 0

a+1

#### Quantity B

$\frac{1}{a}$ - 1

-1 < x < 1

|1-x|

#### Quantity B

1

There are two parallel lines, and the third line intersects these two lines.

#### Quantity A

The number of points with equal distance from three lines

#### Quantity B

3

Two sides of an isosceles triangle have lengths 5 and 5.

#### Quantity A

The perimeter of the triangle

#### Quantity B

15

Eight students of different heights need to be arranged into two rows of seats. Each row has four seats. For each column, the student in the row ahead needs to be shorter than the student in the row behind. In how many ways can these students be arranged?
An urn contains 4 red balls, 8 green balls and 2 yellow balls. Five balls are randomly selected WITH replacement from the urn. What is the probability that 1 red ball, 2 green balls, and 2 yellow balls will be selected?

An eight-digit integer is formed by three "1" and five "2". How many different such integers can be formed?
Event A and event B are independent event. If the probability that even A occurs is 0.4 and event B occurs is 0.3, what will be the probability that at least one event occurs?

In an equilateral triangle ABC,three points P,Q and R are on the side AB,AC and BC, respectively.

#### Quantity A

The sum of any two interior angles in Δ ABC

#### Quantity B

The sum of any two interior angles in Δ PQR

a

b

x

#### Quantity B

90

△ABC is an isosceles triangle, BA=BC, DE is parallel to AC. If the perimeter of both triangle BDE and quadrilateral ADEC equals to 18 (the length of all the sides are integers), then what is the length of DE?
A committee of 4 people consisting of 2 men and 2 women is to be selected from 5 sets of fraternal twins, where each set consists of one man and one woman. If only 1 person from each set of twins may be selected for the committee, what is the total number of distinct committees that can be formed?
How many integers between 100 and 1,000 are multiples of 7?
How many of the multiples of 3 between 100 and 200 are odd integers?
In the xy-plane, the point (t, t-1) lies on the line with equation y = $- \frac{1}{2}$ x +$\frac{1}{3}$ . What is the value of t?

If $n^{k}$=10r+3, then n could be?